Management

• The ideal haemoglobin level for optimal oxygen carriage and viscosity remains contentious. A recent multicentre trial showed improved outcomes if a trigger of 7 g/dl was used. A higher transfusion threshold, e.g. 9-10 g/dl, may be needed in those with cardiorespiratory disease.

• Transfusion is usually given as packed cells with or without a small dose of furosemide to maintain fluid balance. This may need to be given rapidly during active blood loss, or slowly for correction of a gradually falling haemoglobin level.

• Rarely, patients admitted with a chronically low haemoglobin, e.g. <4-5 g/dl, which often follows long term malnutrition or vitamin deficiency, will need a much slower elevation in haemoglobin level to avoid precipitating acute heart failure. An initial target of 7-8 g/dl is often acceptable. Obviously, this may need to be altered in the light of any concurrent acute illness where elevation of oxygen delivery is deemed necessary.

• Erythropoeitin reduces the need for blood transfusion in long-term ICU patients and may be useful in those with multiple antibodies or declining transfusion for religious reasons.